The present invention relates generally to packings for use in an annular packing space between a first cylindrical member which reciprocates within a cylindrical bore of a second member, and more particularly, but not by way of limitation, to such packing sets specifically designed for use in sealing the high pressure ends of a reciprocating plunger pump utilized for pumping fluids and slurries.
Reciprocating pumps and packing seals therefor are generally known with respective examples being shown in U.S. Pat. No. 5,647,737, the disclosure of which is incorporated herein by reference. These reciprocating pumps are operatively connected to a reciprocating drive means such as a piston type motor by a piston tube. The piston tube is directly connected to the base of the motor and encloses a reciprocating pump member which includes a number of seals.
Typically in high pressure reciprocating pumps, the seal between the reciprocating plunger and the cylinder comprises a packing arrangement including a plurality of V-shaped packing rings held in longitudinal compression with various male and female adapters at the forward and rearward ends of those packing sets. Generally, an upper packing arrangement and a lower packing arrangement is provided with the upper packing arrangement being stationary within the piston tube and the lower packing being located at and being movable with the end of the reciprocating plunger in the piston tube.
Very high pressures on the order of many thousands of pounds per square inch are typically involved in pumping operations involving these reciprocating pumps. Additionally, the fluids in the case of slurries are often very abrasive because they carry large quantities of solid particles therein. As a result, a very difficult sealing problem is encountered at the high pressure end across the lower packings of these pumps, where the fluid or slurry must be prevented from leaking between the reciprocating plunger and the cylinder within which it reciprocates. This leaking problem is further exacerbated by deterioration problems encountered in the use of such packings including the deterioration of the V-shaped packing rings due to the hydraulic load from the high pressure fluid end of the pump.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including the features more fully disclosed hereinafter.
In one aspect of the present invention, this is accomplished by providing a packing assembly for sealing a space between a pump plunger and a pump body of a reciprocating plunger pump with a plunger having a pumping end with an outer perimeter. At least one seal is disposed around the pumping end of the plunger and a securing member having a first end capable of attachment to the pumping end of the plunger. A second end having a flange with an outer perimeter greater than the outer perimeter of the pumping end of the plunger is also provided, such that when the first end of the securing member is attached to the pumping end of the plunger, the second end maintains the at least one seal disposed around the pumping end of the plunger.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.